Executive brief
Parse Server is an open-source backend used to build and host applications. A security flaw in its real-time update feature (LiveQuery) allows logged-in users to bypass privacy settings that are supposed to hide specific sensitive data fields. By exploiting this, an attacker could potentially figure out the contents of private information they are not authorized to see.
Technical details
A type confusion vulnerability (CWE-843) exists in Parse Server's LiveQuery implementation. Authenticated users with 'find' class-level permissions can bypass 'protectedFields' restrictions by submitting a subscription query where logical operators ($or, $and, or $nor) contain an 'array-like' object (a plain object with numeric keys and a length property) instead of a standard array. This bypasses the protected-field guard, allowing the subscription event to act as a binary oracle. Attackers can use this to systematically infer the values of protected fields. The issue is fixed in versions 8.6.70 and 9.7.0-alpha.18.
Affected products
- Parse Community Parse Server < 8.6.70, >= 9.0.0 < 9.7.0-alpha.18
Timeline
- 2026-03-29: advisory: GitHub Security Advisory GHSA-mmg8-87c5-jrc2 published
- 2026-03-29: patched: Fixes merged into release branches
- 2026-03-31: disclosed: CVE-2026-34595 published
References
- https://github.com/parse-community/parse-server/commit/f63fd1a3fe0a7c1c5fe809f01b0e04759e8c9b98
- https://github.com/parse-community/parse-server/commit/ffad0ec6b971ee0dd9545e1bf1fb34ddebf275c2
- https://github.com/parse-community/parse-server/pull/10350
- https://github.com/parse-community/parse-server/pull/10351
- https://github.com/parse-community/parse-server/security/advisories/GHSA-mmg8-87c5-jrc2